GEOTECHNICAL INVESTIGATION OF AN EMBANKMENT SLOPE FAILURE ON THE CAMPUS OF JAMES MADISON UNIVERSITY

In March, 2013, an embankment slope on the campus of James Madison University began to fail and was eventually in need of repair requiring the removal of the section of the embankment that failed, and the construction of a retaining wall in its place. An embankment slope should be designed in such a way that its factor of safety against failure is greater than 1, resulting in a stable and long-standing structure. The embankment in question had a gentle slope angle of 16.3° that would be expected to have a high factor of safety, and therefore failure should have been unlikely. This project is a geotechnical investigation to identify the causes of failure of such a gentle embankment slope. Intact samples of the embankment soil were collected and classified as CL using the unified classification system. Cohesion and friction values of 79.91 kPa and 13.43°, respectively, were determined using direct shear testing. After surveying the embankment, Slide 6.0, from the RocScience suite of geotechnical software, was used to employ Bishop’s simplified method of slope analysis to determine the factor of safety. Preliminary analysis resulted in a factor of safety of 1.14, suggesting other factors in addition to soil strength might have caused the failure. More stability analyses will be performed and drilling data will be investigated to pinpoint the possible factors that led to failure of the embankment. Based on the conclusions of this project, the stability of other embankment slopes on the JMU campus will be evaluated.